丙戊酸钠抑制脯氨酰内肽酶活性对非酒精性脂肪性肝病进展的影响

Effects of sodium valproate on the progression of non-alcoholic fatty liver disease by inhibiting prolyl endopeptidase activity

目的:探索丙戊酸钠对高脂高胆固醇饮食诱导的非酒精性脂肪性肝病(NAFLD)模型小鼠的影响。方法:随机选取42只7~8周龄雄性C57BL/6J小鼠分为对照组、模型组和干预组。对照组饲以标准饲料,模型组及干预组饲以高脂高胆固醇饲料,8周后干预组给予丙戊酸钠(0.4%丙戊酸钠饮用水),对照组和模型组给予常规饮用水,继续干预8周后处死小鼠。观察小鼠体质量、肝指数、血清生化指标和肝组织病理学改变,并探究其与脯氨酰内肽酶(PREP)之间的关系。结果:与对照组比较,模型组小鼠的体质量、肝指数、脂睾指数均显著升高(P<0.05);与模型组相比,干预组肝指数显著下降(P<0.05),但体质量、睾脂指数差异无统计学意义(P>0.05)。模型组小鼠血清总胆固醇(TC)、低密度脂蛋白(LDL)、甘油三酯(TG)、谷丙转氨酶(ALT)、碱性磷酸酶(ALP)、空腹血糖(FBG)、空腹胰岛素均显著高于对照组(P<0.05);干预组小鼠血清TC、TG、ALT较模型组显著下降(P<0.05),LDL、谷草转氨酶(AST)、ALP、FBG、胰岛素与模型组比较差异无统计学意义(P>0.05)。模型组小鼠肝脏出现明显的脂肪变性、炎症及气球样变,经丙戊酸钠干预后,脂肪变性和炎症明显改善,NAFLD活动度积分(NAS)显著下降(P<0.05)。模型组肝组织PREP mRNA RQ值为2.02±0.13,PREP蛋白活性为(473.39±15.41)pmol·mg^(-1)·min^(-1),均较对照组高(P<0.05);干预组肝组织PREP mRNA RQ值为1.86±0.18,与模型组比较差异无统计学意义(P>0.05);干预组PREP蛋白活性为(397.41±9.63)pmol·mg^(-1)·min^(-1),较模型组低(P<0.05);三组之间肝组织PREP蛋白表达水平差异无统计学意义(P>0.05)。结论:丙戊酸钠能通过抑制PREP活性改善NAFLD模型小鼠肝脏的脂肪变性和炎症。

Objective:To investigate the effect of sodium valproate on mice model of non-alcoholic fatty liver disease(NAFLD)induced by high-fat and high-cholesterol diet.Methods:Forty-two male C57BL/6J mice aged 7-8 weeks were randomly divided as the control group,the model group,and the intervention group.The control group was fed with standard diet,and the model group and the intervention group were fed with high-fat and high-cholesterol diet.Eight weeks after initiation of the experimental diets,the intervention group was given sodium valproate(drinking water with 0.4%sodium valproate)for 8 weeks,while the control group and the model group were given the regular drinking water.Mice were sacrificed after the experiment.The body weight,liver index,serum biochemical indexes,liver histopathological changes,and the relationship with prolyl endopeptidase(PREP)were observed in all mice.Results:Compared with the control group,the body weight,liver index and epididymal fat index of the model group were significantly increased(P<0.05).Compared with the model group,the intervention group had statistically decreased liver index(P<0.05),but there was no significant difference in body weight or epididymal fat index between the two groups(P>0.05).Serum total cholesterol(TC),low-density lipoprotein(LDL),triglyceride(TG),alanine aminotransferase(ALT),alkaline phosphatase(ALP),fasting blood glucose(FBG),and fasting insulin(Insulin)in the model group were significantly higher than those of the control group(P<0.05);compared with the model group,TC,TG and ALT in the intervention group were significantly decreased(P<0.05),while there was no statistical difference in LDL,AST,ALP,FBG,and Insulin between the two groups(P>0.05).The liver tissue in the model group showed obvious steatosis,inflammation and ballooning.After intervention with sodium valproate,steatosis and inflammation were markedly attenuated,and NAFLD activity score(NAS)was significantly decreased(P<0.05).In liver tissue of the model group,the RQ value of PREP mRNA was(2.02±0.13)and the protein activity of PREP was(473.39±15.41)pmol·mg^(-1)·min^(-1),both higher than those in the control group(P<0.05).In liver tissue of the intervention group,the RQ value of PREP mRNA was(1.86±0.18),showing no significant difference from that of the model group(P>0.05);however,the protein activity of PREP in the intervention group was(397.41±9.63)pmol·mg^(-1)·min^(-1),significantly lower than that in the model group(P<0.05).There was no statistical difference in the PREP protein level in liver tissues of three groups(P>0.05).Conclusion:Sodium valproate can attenuate liver steatosis and inflammation in NAFLD mice model by inhibiting PREP activity.